US1333802A - Load-indicator - Google Patents

Description

H. WI FLETCHER.

LOADV INDICATOR.

APPLlcAxoN FILED MAR. 18, 1919.

lPatented Mar. 16,1920.

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LOAD INDICATOR.

APPLICATIONFILED MAR-18, 1919.

PatentedfMar. 16, 1920.

2 SHEETS-SHEET 2.

Il. ll`llul=== Ngs z HAROLD W. FLETCHER, OF HOUSTON, TEXAS.

LOAD-INDICATOR.

Speccaton of Letters Patent.

Patented Mar. 16, 1920.

Application filed March'lS, 1919. Serial No. 283,393.

To all whom. 'it may concern.'

KBe it known that I, HAROLD FV. F Eroi-inn, a citizen of the United States, residing at I-Iouston, Harris county, ril`exas, have invented a certain new and useful Improvement in Load-Indicators, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

My .invention relates to improvements in load indicators for use in registering the weight which is suspended upona cable or other sustaining device. It may be used wherever it is to advantage to note the load suspended upon a line but has special application to well drilling for oil, water or gas. It is very difficult in drilling operations te tell when the proper amount of weight is resting upon the drill as it is operating in the bore hole. The string of pipe and the bit at the lowei' end orD the well are suspended by a cable during the operation, said cable running over a crown block at the top of the derriclr. The driller operating the drill learns by experience to tell about when the proper weight is resting upon the drill by resting his hand upon the cable and the sustaining drum, but this is a very inaccurate method and only the most experienced drillers can gage the weight, with even a rough degree otl accuracy. As the weight of the drill stem above the drill in a deep well is ofttimes excessive and amounts, in most cases, to a number of tons weight, it is necessary, in order that the bit operate correctly, and that the same be not crushed by the excessive weight allowed to rest upon the bit, that a large proportion of the weight of the drill stem, above the drill, be borne by the sustaining cable.

In my co-pending application No. 274,118 filed January 30th, 1919, I have described my preferred method of attaching a load indicator in the load sustaining cable. It is customary to pass the cable from the rotary drum, on which it is reeled, up over the crown block at the top of the derrick and down around the traveling block. It is customarily passed from the crown block two or three times down around the traveling block, the end being again passed over the crown block and back for attachment to the housing of the traveling block, thus allowing live or seven strands supporting the load. rlhe :forward end of the cable is usually called the deadline vand may be carried down from the crown 'block for attachment to the mudsill of the derricl. In the use of my invention this arrangement is preferable for the indicator is thereby placed where it may be easily consulted and but a small proportion of the actual weight of the drill stem exerted upon the indicator.

One object of my invention is to provide an indicator which may be easily attached to the cable sustaining the weight of thel drill stem to be measured and which will show directly the amount oi weight being borne by the drill at the bottom ot the well l at any time.

Another object is to provide a load indicator, the dialv on which may be set at zero when the full weight of the drill is borne by the cable and which will then read directly to show the amount of weight resting upon the drill thereafter. Other objects and advantages will appear in the specilication which follows.

Referring to the drawingsl forming a part of this speciicati'on and in which like numerals are applied to like parts throughout the several views, Figure 1 is a central, longitudinal section through my improved load indicator, the central shait thereof being shown in elevation forthe purpose of clearness. Fig. 2 is a side elevation of the same taken at right angles to the view shown in Fig. 1.certain parts being broken away for greater clearness, Fig. 3 is a view similar to that shown in Fig. 1, illustrating a second embodiment of my invention; Fig. et is a. side elevation at right angles toy that shown in Fig. 3; certain parts `being broken away.

The body of my improved load indicator is made up of a. 'cylindrical casting 1, having a lower internally threaded nipple 2 thereon, into which is threaded a length or' pipe 3. Threaded on to the lower end il of the pipe 3 is a cap 5 adapted to close the end of said pipe. 'A circular opening 6' formed centrally of the cap 5 forms a bearing in which a rod or shaft 7 is adapted to reciprocate. This shaft has an-outer eyelet 8 for attachment to a cable or other sustaining means. rihe upper end of the shaft 7 is threaded at 9 for attachment to the nut l0. The nut 10 and the lower cap 5 of the housing form seats for a helical spring 11 which surrounds the shaft 7 and acts to force vthe nut l() and the shaft 7, retained therein, toward the upper end of the housing 3.

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At the upper end of the member 1, another internally threaded nipple 12 is formed, into which is threaded a length of pipe 13 forming a housing for other working parts or" my device. The upper end ot this pipe 13 is threaded into engagement with a closing cap 1e.- having an upper eyelet 15 for attachment to another section of the cable or similar attaching means.

rlfhe central section ,of the-body member 1,

is bored along its longitudinal axis to formv upper and lower bearings 16 and 17, adapted to receive a shaft 18 somewhat smaller in diameter than the lower shaft 7. This shaft 18 has resting on its upper end a cup shaped head 20 forming a seat for a smaller helical spring 21 which bears at its upper end against the cap 1st, thus serving to press the s vraft 18 resiliently downward in the housing 13. rThe lower end of the shaft 18 is adapted to seat upon the upper end or the shaft 7 and is held in engagen'ient therewith by the spring 21. One side oif the shaft 18 is recessed or cut away somewhat, at 22, to form a flattened surface upon which are cut the raclr teeth 23, these teeth extending downwardly to a point aced somewhat above the lower end of the shaft.

rllhe central portion of the bearing member 1 is provided with a transverse cylindrical opening or housing 2-1, closed on one side 25 by the walls ot the housing 1, and on the other side by a removable cap 2G, the inner face ot which is provided with a laterally extending boss 27 forming a bearing for one end of a small transverse pin or shaft 28. The wall 25 is also provided with an opening 29 forming a bearing for the other lend oit the pin 28. r)The pin 23 projects a short distance beyond the, walls 25 and upon this projecting portion is detachably secured a flattened circular plate, or disk, 30 on the outer margin of which is fastened an annular dial plate 31 provided with graduated scale divisions 32.

rElie central portion or the shaii 28 is provided with a small pinion 33 fixed on the shai'ft and meshing with the rack teeth 23 upon the shaft 18. The dia-l plate 30 is inclosed, except on the forward face, within a circular housing 311 integral with the side vvalla oi. the central body portion 1. A laterally projecting annular iange 35 on said housing 3a surrounds the dial plate and an open cover-shaped indexing member 36 its over the flange 35 and is held in place thereon by means of a number oit set screws 37 in the sides thereof, said set screws adapted to tit behind an annular ring' or lange38 on the outer tace oft the wall 35. Between the flange 38 and the outer edge of the wall 35 is located a lea-f spring This spring is sinucus in form and is adapted to exert a resilient pressure upon the fla-nge 35 and the inwardly projecting wall of the indexing member 3G, thereby holding the indexing member against accidental rotative movement.

In the operation of this device one end is secured by means of the eyelet 15 to the lower end of the dead line of the cable; the other end is secured by means of the eyelet 8 to another section 'of cable, through which it is secured to the mud-sill o1c the derriclr. 1n order that the dial may be set so that it will face inwardly toward the driller at all times, a laterally projecting eyelet 40 is formed on the side of the central member 1. rlhrough this eyelet an anchoring rod is secured, said rod being fastened at the opposite end to the frame work ot the dei-rick in such manner as to hold the 'tace of the dial inwardly toward the driller. 1t is obvious that the load indicator may be secured in the cable at any desired point, but the saine'is preferably positioned in the manner described because more convenient of access and because, in this position, it does not sustain the full weight of the drill stein and the bit attached thereto.

Then the cable has four strands connecting the crown bloclr with the traveling block, the weight sustained, or force exerted, upon the dead line to which the indicator is secured will be of the iull weight of the load sustained` by the traveling block. It the said cable is passed three times around the crown block and the traveling block, thereby providing six strands of the cable between the crown block and the traveling block 2,- ot the weight will be exerted upon the indicator in the position described.

The load, including the total weight sustained by the traveling block, is lifted from the bottoni of 'the well and this load will serve to compress the spring 11 within the housing 3, and when the shaft 7 is thus pulled downwardly inv the housing 3 against the action oit the spring 11, the spring 21 in the upper housing 13 will exert sufhcient pressure upon the shaft 18 to cause this shaft to follow downwr rdly in its bearing. This movement ot the shaft 18 will, through means of the pinion. and the 'sha'lit 28, cause the dial plate 31 to rotate in a clockwise direction in its housing. lvhen the full weight oit the drill stem and drill are sustained by the cable, and the dial comes to rest, the indexing portion 3G is rotated by hand against the friction exerted by the I spring 39 until the indexing notch 41 comes opposite the zero point upon the scale. The bit and drill stem are then lowered upon the bottom of the well until the proper weight desired rests upon the bit. As the weight is gradually talren oilA of the cable and part thereoi1 is sustained by the bit on the bottom of the well, the dial 30 will rotate baclrwardly again in al counter-clockwise direction. The dial is so numbered that the amount of the released weight will read directly. The weight sustained by the bit at all times can therefore be rea-d directly upon the scale 32 of the dial. As shown inFig. 2 theamount of weight resting upon the drill whenf there are four strands of the cable between the crown block and the travcling block would be read upon the outer* circle of the dial; and when as shown in this view, would be slightly over 1800 lbs.`

If, however, there were six strands of cable between the crown block and the traveling block the readingwould be upon the scale on the inner circle of the dial and the reading would then be slightly over 2700 lbs.

It is obvious that when the indexing point 41 has been set at zero of the scale, as the entire load is sustained upon the cable, then the amount of weight subsequently borne by the bit will be the reading upon the scale at any time. It will therefore be possible for the driller to lower the cable until the exact weight desired rests upon the drill and this weight may `be maintained with fairly delicate degree of accuracy. By the use of this device, even an inexperienced driller can tell at once what weight is being `borne by the bit and it will thus be possible tol have the proper weight resting upon the bit at all times.

The shaft 18 is made separate from the shaft 7 instead of integral therewith in order that any sudden dropping or jerking of the load upon the cable will not affect disastrously the mechanism connected with the dial, the dial being actuated in its clockwise rotation only by the force of the spring 21 which may be just suhcient to cause the shaft 18 to move downward into contact with the upper end of the shaft 7.

In Ithe modification shown Ain Figs. 3 and 4 the lower and upper housings 3 and 13 and the shafts 7 and 18 respectively therein, are arranged in the same manner as disclosed in Figs. 1 and 2. The central housing or body member 1 is formed somewhat differently, however, to accommodate a different ar.- rangement of the registering means used with this modification.' The shaft 28 upon which the registering dial 30 is mounted is supported within a remoif'able bearing member 42, said bearing being formed integral with an outwardly flaring housing provided at its outer. periphery with an outwardly extending flange over which is fitted a cover-shaped indexing member 36. `The removable bearing 42 and the outer housing member 85 are secured within a conical-shaped recess in the side of the central housing 1 by means of set screws 43, 43 which pass through the outer housing member 535 and the outer face 44 of the eon ical-shaped seat 45 of the ycentral housing member 1. The inner end of the shaft 287 is provided with a pinion 33, adapted to mesh with the rack teeth 23 upon the shaft 18 as in the previous modification. The dial 31 is secured to the dial plate 30 as in the previous modification. rllhe dial plate 30 is, however, provided with a central inwardly extending bearing portion 46, through which the outer end of the pin 28 fits. Between the bearing member 46, and the outer end' tween which and the central portion of thel dial plate is fitted a brake band 50. The outer end of the pin 28 is provided with a nut 5l and a washer 52 which forms a seat for a helical spring 53, this spring bearing at its inner end against the brake member 48 serving to hold the same resiliently against the brake band 50. The brake member 48 is held non-rotatably upon the pin 28 by means of a key 5G upon which the said brake drum is slidable. Immediately arount the outer edge of the flange 49 of thefbrake member is a forwardly projecting flange 54, which is preferably roughened somewhat on the outer surface to provide a hold for turning the dial plate 30 against the action of the brake member 48, this flange 54, being integral with the said dial member 30. The outer registering member 36 in this modification is fixed rigidly to the housing member by means of setscrews S5. Lu-

brication may be supplied to this devic\ through the openings 59 in the side`of the housing 1 3, this lubrication acting to pass downwardly around the shafts 18 and 7 in an obvious manner. rlhe outer dial operating mechanism is lubricated through a small opening 57 in the upper surface of the housing 45, the lubricant in this case being received within the small cup 58 in the upper face of the bearing` 42.

In the operation of this modified form, the loadindicator is secured upon the cable as in the other modification. The weight or load resting upon the bit at the bottom of the hole is measured in the same manner as described in connection with Figs. 1 and rlhe registering notch 41, however is stationary and the dial itself is turned by gripping the outer flange 54 of the dial plate and turning the' dial against the action of the friction brake so,that zero of the scale will Vcome directly opposite the notch 41. Then the lead is then allowed to rest gradually upon the bit at the bottom of the well the weight taken from the cable will be registered upon the dial as before, it being obvious that the pressure of the brake member 48 upon the dial will cause the same to ro- Vin said housn tate with the shaft 28 under normal conditions. lt will thus be noticed that this modification is the same in principle as that disclosed inthe previous embodiment, the difference being,` that, in this modification, the dial may be turned upon the pin, when necessary to set the same at Zero, while the total weight of the drill and drill stem are sustained by the cable. Y Y

This type of indicator has the advantage of being adjustable so that the weight resting upon the bit may be readat any time as the drilling` operation proceeds. Extra lengths of drill stem are added at intervals, thereby gradually increasing the weight sustained by the cable. But each time the bit and drill stem go into the hole, the total weight thereof will be allowed to rest upon the cable and the dial of 'the indicator' will be set so that Zero will be opposite the registering notch al. rlhereafter the amount of weight taken off the cable and borne by the bit at the bottom of the well will read directly upon the dial of the indicator, thus 1 aliing it possible to learn the weight resting upon the drill at all times. The difliculty ordinarily experienced of overloading' the drill'and thereby causing excessive wear and breakage of the parts of the drill will be avoided.

Having thus described my invention the advantages of which will be clear without further description, what l claim as new and desire to protect by Letters Patent is:

1. ln a load indicator, a longitudinal housing, a lower shaft therein, said shaft having,` a compression spring thereon, an upper shaft resting on said lower shaft, means holding` said upper shaft resiliently against said lower shaft, a transverse spindle rotatable by said upper shaft, a dial on said spindle, an indexing` means outside said dial and means to cause the zero point on said dial to register with said indexing means when the load is sustained by said lower shaft, and means on said dial to indicate directly the amount of load released thereafter.

Q. .in a load indicator, ahousing, a spring pressed shaft inthe lower portion thereof, an upper shaft, means to hold said upper shaft resiliently against the upper end of said lower shaft, a raclr thereon, a transverse spindle, a pinion thereon meshing with said rack, a dial on the outer end of said spindle, a friction means to hold said dial rotatably with said shaft, and anV indexing means outside said dial.

3. In a load indicator, a longitudinal housing, a compression spring` in the lower portion thereof, a shaft reciprocable against the action of said spring, a transverse spindle Y a dial plate rotatable with said spindle, means actuated by said shaft 'and said spring to rotate said spindle and means adjustable relative to said shaft to set said dial at Zero when desired irrespective dicate directly the weight released fromr said first named shaft when the load is sustained by said shaft.

5. A load indicator, comprising a housing, a load supportingshaft therein, means to normally force said shaft upwardly vin said housing, an 'indicator shaft resting on said load shaft, means to hold said indicator shaft resiliently downward, a dial, connecting means between said indicator shaft and said dial to rotate said dial when a load'is sustained on said load shaft, means to set said dial at Zero when the load is supported by said shaft, said dial being so calibrated ann numbered as to indicate directly thereafter the amount of load released from ysaid load shaft.

6. ln a load indicator', the combination of a housing, a. load shaft, means to hold said load shaft resiliently upward in said housing, an upper shaft resting on load shaft, a sprin holding saidl upper shaft against said load shaft, a raclr on said upper shaft, a transverse spindle, a pinion thereon meshing' with said rack, a dial on the outer end of said spindle, friction means to hold said dial rotatably on said spindle, andan indexing means outside said dial whereby said dial may beset at zero when a load is sustained by said load shaft, said dial being so graduated and numbered as to indicate directly the amount of load released thereafter.

7. ln a load indicator, the combination of a load shaft, a spring to sustain said shaft, an indicator shaft, means to hold said indicator shaft against said load shaft', a dial, means connected with said indicator shaft to rotate said dial when a load is placed on said load shaft, an index outside said dial and friction. nr'eans whereby said dial may be set to zero relative to said index, said dial being Graduated to read directly the amount of load thereafter released.

in testimony whereof, l hereunto affix my signature this the 13 day of March, 1919.

HARQLD lV. FLETCHER.

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